DESCRIPTION This application is based on the finding that beta receptor activation in conjunction with low frequency stimulation induces long term potentiation (called AC-LTP) in young rats but not in aged animals. The findings that aged rats have intact high frequency stimulation induced LTP and reduced short term responses to a beta agonist and forskolin suggest that a site after receptor activation is involved. The goal of this grant is to determine the biochemical defect, to determine if it is pre- or postsynaptic and to correlate changes in AC-LTP with spatial learning.